Spot-welding thin sheets.



E. THOMSON.

SPOT WELDING THIN SHEETS. APPLIeATioN mmm mulo, 1913.

Patented Feb. 3, 1914.

' w/r/vfs E84 TTUH/VEYS tain new ELIHU THOMSON, OE SWAMPSCOTT,

TYSSACHUSETTS, ASSIGNOR TO THOMSON ELECTRIC WELDTNG COMPANY, OE LYNN. MASSACHUSETTS, .A lCORPORATION 0F MASSACHUSETTS.

Lessico.

`Specification of Letters Patent.

SPOT-WELDING THIN SHEETS.

Patented Feb. 3, 1 914.

Application filed May 10, 1913. Serial No. 766,72

To all whom it may concern Bc it known that I, zen ot the United States, and a resident ot Swampscott, in the county Ot Essex and State ot Massachusetts? have invented cerand useful Improvements in Spotlelding' Thin Sheets.4 ot' which the 'following is a specitieation.

My invention relates to the art ot unitingr plates or sheets ot metal by, the process knoivn as electric. spot yielding and more particularly to that special method oi practising' the art in which the spots et welded union are produced 'by a pointed electrode or electrodes forced against 'the metal sheets` at the spot to be Welded and servingat 'the same time to pass the Welding' euri-ent through the pieces.

The object of the invention is to avoid the ditlieulties experienced in the process heretofore practised from the tendency ot the metal sheets or plates, particularly when they are made or" very'thin sheet metal. to

buckle or draw 1n their uinvelded portions. owing to the inequality ot. the heating' and pressure as between the portions involving` the -Welded spots and the nnivelded portions or areas.

My invention consists essentially in clamping the univelded portions of the thin sheet metal plates that are to he Welded so as 'to press them irmly together and, While maintaining suoli clamping` pressure. mal;- ing the electric spct'iveld by the application of the pointed electrode at the unelaniped part of the plate Where the Weld to be made.

The accompanying drawings show in Figure l in cross-section devices that may he employed for practising the invention as applied to the spot Welding of two thin metal sheets at a number ot spots. Fig. 2 is a plan of the same apparatus. 3

shows a modification ott the appliances that vmay be employed in carryrne out the process.

the two thm plates or.

Referring' to Fig. 1, sheets ot metal to he Welded toeether at a spotor spots are indicated at 2, Wniie 3 indicates pointed welding electrodes of any desired form or character adapted tor electrically Welding the sheets together in a spot or spots.

Tn .the practice ot my invention as illustrated in Fig. l, tivo such electrodes are shown as employed, adapted to press the ELIHU THoMsoN, a citil l i l nin-l together between them. My invention however is not limited to such use ot tivo pointed electrodes but may be employed where one only ot them is pointed and as will be presently described.

tsindicates tivo rigid plates perforated at spots coinciding` with the spots to be welded and between which the plates 2. Q are inserted and .firmly clamped together by any desired mechanical appliance, prior to the eeetrie Welding' operation proper. These plates .should be adapted to clamp the sheet nwtalplates very tirmly immediately rnun'd the spots to be Welded, although for he best elect the clamping ot the surface ot the sheet nir-tal plates should be over their whole uun'elded areas. Aitor the clamping' has been eit'eeted and ivhile it is maintained the electrodes 3 are applied to exert pressure in the spots ot welded union and to Ytarnish the heating current as ivell understood in the art.

-X number ot spots ot Welded union'distributed over the Whole areav of the plates 2- may be made one at a time by the application oi' the electrodes through the openings in the clamping devices or. as Will be obiious, the welding` pressure by means of electrodes may be applied at all of said spots atonee a'tter the necessary clamping` pressure has been applied by the plates 4.

lu the moditieation illustrated in Fig. 3, but one pointed electrode 3 is employed and the opposite eleetrode 3 is shoivn as a block area larger than the spot and serves likeaise as the, under'one ot the clamping` blocks .r plates 4v. The devices shoivn in Fig'. 3 are employed in the same manner as in the as oit the devices shoivn in Fie: l, the ot metal being' first clamped {irmly between. the plates L'i' and 3 and thereafter, and While clanuiing pressure is maintained` the electroder inserted through the opening` in the clamping); plate. and the Welding pressure and heating current are applied at the spot ot -.v:lded union.

i'lhat i l' as my invention iszi. The lured/leser' ed improvement in 'cldiujj she metal at a spot or spots by the eieetrode prece i, consisting in clamping` the sheets lirmly e tether over their univelded areas or portions not to be Welded and then, vfhile maintaining' the clamping` pressure, applying` the Welding' pressure and current at the unclamped part or spot to be Welded.

g I :Liese 2. The improvement in Welding tWo 'thin sheets of metal together by the electrode welding process, consisting in clamping the t-Wosheets or plates of metal together.. leaving both of them exposed at the spots of welded union and While maintaining the ypressure e'ectng the Weld atseicl spots by the electrode process.

3. The heleindesclhecl improvement in the electric Welding of two thin sheets of metal together at a spot in their opposed areas, consisting in clamping them rmly together immediatelyaound said Spot, leaving the points to be Welclecl expose@ for :1pe plcaton of the Welcling current and pres .sure and then, While maintaining" the clampH ing pressure, ellfectng the Welding at said spot.

Signed at Lynn in the county of Essex and State of fvassaehusetts this 2nd clay of May A. D. 1918.

ELIHU THOMSON.

TWit-n esses JOHN il. MGMANUS, Jr., HENRY A. ANDERSEN. 

